code: def bin_train_data(train_data):
      X, y = train_data
      X_bin = X[y <= 1]
      y_bin = y[y <= 1] * 2 - 1
      return X_bin, y_bin
  
file_path: lightning/lightning/impl/tests/conftest.py
imports: import pytest
  import scipy.sparse
  from sklearn.datasets import load_iris
  from lightning.impl.datasets.samples_generator import make_classification
label_desc: Use image node_id 2 for calling a global function with example usage: bin_train_data(train_data) and returns: X_bin,  y_bin